Damping cylinder

Abstract

A damping cylinder ( 100 ) is provided. The damping cylinder ( 100 ) comprises a housing ( 101 ) and a piston cylinder ( 201 ) located within the housing ( 101 ). A piston rod ( 103 ) extends from the housing ( 101 ) and the piston cylinder ( 201 ). The damping cylinder ( 100 ) can also include a piston ( 203 ) coupled to the piston rod ( 103 ). The piston ( 203 ) is movable within the piston cylinder ( 201 ) and separates the piston cylinder ( 201 ) into a first fluid chamber ( 210 ) and a second fluid chamber ( 211 ). The damping cylinder ( 100 ) can further include a damping module ( 102 ) in fluid communication with the first and second fluid chambers ( 210, 211 ). The damping module ( 102 ) includes a pressure relief valve ( 221 ) configured to provide a first damping level and a directional control valve ( 222 ) configured to provide at least a second damping level.

We claim: 
     
         1 . A damping cylinder ( 100 ), comprising:
 a housing ( 101 );   a piston cylinder ( 201 ) located at least partially within the housing ( 101 );   a piston rod ( 103 ) extending from the piston cylinder ( 201 ) and the housing ( 101 );   a piston ( 203 ) coupled to the piston rod ( 103 ) and movable within the housing ( 101 ) and separating the piston cylinder ( 201 ) into a first fluid chamber ( 210 ) and a second fluid chamber ( 211 );   a damping module ( 102 ) in fluid communication with the first and second fluid chambers ( 210 ,  211 ) and including:
 a pressure relief valve ( 221 ) configured to provide a first damping level; and 
 a directional control valve ( 222 ) configured to provide at least a second damping level. 
   
     
     
         2 . The damping cylinder ( 100 ) of  claim 1 , further comprising a damping fluid reservoir ( 240 ) in fluid communication with the first and second fluid chambers ( 210 ,  211 ) via fluid lines ( 232 ,  233 ) and in fluid communication with the damping module ( 102 ) via a fluid line ( 234 ), wherein the fluid lines ( 232 ,  233 ,  234 ) are located within the housing ( 101 ). 
     
     
         3 . The damping cylinder ( 100 ) of  claim 2 , further comprising a check valve ( 235 ) positioned in a fluid line ( 232 ) providing fluid communication between the damping fluid reservoir ( 240 ) and the first fluid chamber ( 210 ). 
     
     
         4 . The damping cylinder ( 100 ) of  claim 2 , further comprising a check valve ( 236 ) positioned in a fluid line ( 233 ) providing fluid communication between the damping fluid reservoir ( 240 ) and the second fluid chamber ( 211 ). 
     
     
         5 . The damping cylinder ( 100 ) of  claim 2 , wherein the damping fluid reservoir ( 240 ) is located within the housing ( 101 ). 
     
     
         6 . The damping cylinder ( 100 ) of  claim 1 , further comprising a check valve ( 237 ) in a fluid line ( 230 ) providing fluid communication between the first fluid chamber ( 210 ) and the damping module ( 102 ). 
     
     
         7 . The damping cylinder ( 100 ) of  claim 1 , further comprising a check valve ( 238 ) in a fluid line ( 231 ) providing fluid communication between the second fluid chamber ( 211 ) and the damping module ( 102 ). 
     
     
         8 . The damping cylinder ( 100 ) of  claim 1 , wherein the damping module ( 102 ) further includes a throttle ( 220 ) located in parallel with the pressure relief valve ( 221 ) and in fluid communication with the damping fluid reservoir ( 240 ). 
     
     
         9 . The damping cylinder ( 100 ) of  claim 1 , wherein a cross-sectional area of at least one of a plurality of fluid lines ( 230 ,  231 ,  232 ,  233 ,  234 ,  239 ,  242 ,  243 ,  244 ) providing fluid communication between the damping module ( 102 ) and the first and second fluid chambers ( 210 ,  211 ) and the damping fluid reservoir ( 240 ) at least partially determine the first and second damping levels. 
     
     
         10 . A method for operating a damping cylinder including a housing, a piston cylinder located at least partially within the housing, a piston rod extending from the piston cylinder and the housing, and a piston coupled to the piston rod that is movable within the piston cylinder and separates the piston cylinder into a first fluid chamber and a second fluid chamber, the method comprising steps of:
 dampening movement of the piston within the piston cylinder at a first damping level by directing a damping fluid through a pressure relief valve as the damping fluid flows between the first and second chambers during movement of the piston; and   dampening movement of the piston within the piston cylinder at one or more additional damping levels by actuating a directional control valve to direct the damping fluid through the directional control valve as the damping fluid flows between the first and second fluid chambers during movement of the piston.   
     
     
         11 . The method of  claim 10 , further comprising a step of directing the damping fluid into a damping fluid reservoir as the damping fluid flows between the first and second fluid chambers. 
     
     
         12 . The method of  claim 11 , further comprising a step of directing the damping fluid through a check valve positioned between the damping fluid reservoir and the first fluid chamber. 
     
     
         13 . The method of  claim 11 , further comprising a step of directing the damping fluid through a check valve positioned between the damping fluid reservoir and the second fluid chamber. 
     
     
         14 . The method of  claim 10 , further comprising a step of directing the damping fluid through a check valve positioned between the first fluid chamber and the pressure relief valve. 
     
     
         15 . The method of  claim 10 , further comprising a step of directing the damping fluid through a check valve positioned between the second fluid chamber and the pressure relief valve. 
     
     
         16 . The method of  claim 10 , further comprising a step of directing the damping fluid through a throttle located in parallel with the pressure relief valve if the pressure in either the first or the second fluid chambers falls below a threshold pressure.